1. Field of the Invention
This invention relates to apparatus and methods for generating electrical power and, more particularly, to novel apparatus and methods for generating electrical power from natural air or water currents.
2. The Prior Art
As a result of the rapid growth of technology in recent years, demand for electrical energy is enormous. In an effort to meet this demand, hundreds of electrical power plants have been built during the last decade. Most of these power plants have been of the more traditional type, e.g. hydroelectric generators and generators driven by the combustion of mineral resources. However, with the demand for electrical power continuing to grow, there is an increasing concern as to feasibility and desirability of using traditional electrical energy sources to supply future energy needs. Many of the present power plants, for example, produce considerable quantities of air and water pollution. The construction of additional dams and hydroelectric generators would have a significant impact on the surrounding environment. Additionally, as natural resources are consumed to produce electrical energy, there is great cause for concern about the possibility of severe resource shortages in future years. Also, the cost of operating traditional electrical power plants that generate electricity by the combustion of natural resources is increasing rapidly. As a result of these concerns, a great deal of attention has been directed toward the development of environmentally cleaner, more economical sources of electrical energy.
One possibility having great potential is the harnessing of the kinetic energy of natural air or water currents. The earth's atmosphere, oceans, and rivers are in constant motion, and if these air and fluid currents could be efficiently used to generate electricity, they would constitute a virtually inexhaustible source of electrical energy.
Unfortunately, major problems have been encountered in developing a structurally sound device which has the surface area needed to generate large quantities of electricity from air or water currents. Windmills and water wheels, for example, are suitable for small generating tasks, but have not proven useful in the generation of large quantities of electricity.
Another problem encountered when attempting to generate electricity from air or water currents is the fact that although there may be a generally prevailing direction of travel, at times the current may approach the generator from virtually any direction. Accordingly, it must either be accepted that the generator will occasionally be idle, or provision must be made to cause the generator device to be properly aligned with the oncoming current. However, as the generator's size is increased, so as to increase its generating capacity, movement of the generator device becomes much more difficult. Thus, those skilled in the art have faced a major challenge in attempting to develop an efficient wind or water powered apparatus having sufficient surface area to generate significant quantities of electricity and which is also capable of being quickly adjusted in response to changes in current direction.
Yet another problem inherent in the use of air or water currents to drive a generator is the fact that the strength of these currents may vary widely from one season to the next, or even from one day to the next. It has proven a very difficult task to provide an apparatus capable of structurally sustaining periods of strong current flow, and yet capable of generating electricity during periods of weak current flow.
A typical approach in the construction of wind or water powered generators has been to interconnect a plurality of individual sail structures so as to form a closed loop, and cause them to travel in an oval-shaped path. As the wind or water current propels the sail structures around the oval-shaped path, the sail structures drive one or more electric generators.
However, devices which incorporate this general concept vary widely in structure. For example, in one such device, the several sail structures are attached to a looped cable which is suspended by a pair of spaced-apart wheels. As the current causes the sail structures to move around the loop, the cable travels around the wheels, thereby driving a single electric generator which is connected to one of the wheels. Other devices accomplish the same result by using a chain and a pair of sprocket wheels in place of the cable and wheels described above. Alternatively, an oval track is sometimes used to support and guide the individual sail structures, and some devices have a separate small generator mounted on each sail structure.
Various methods for aligning loop-type generators with the direction of the air or water current have also been employed. One approach has been to place the device in a canyon or channel, where the air or water current moves substantially in only one direction. This approach is clearly of limited utility.
A more useful approach for aligning the generator devices with an air or water current has been to manually or mechanically vary the orientation of the several said structures as the current direction changes. Such a method has also been used to make minor adjustments in the orientation of the sails of a device placed in a canyon or channel.
When the orientation of the sail structures is varied mechanically, each sail structure typically has a servo-motor attached thereto. A separate apparatus detects the direction of the oncoming air or water current, and the servo-motors are programmed to position the sail structures accordingly. Some devices further have the ability to detect the velocity of the oncoming current. In these devices, the servo-motors are further programmed to orient the sail structures so as to present a minimum resistance in the event that the oncoming current becomes too strong and would otherwise cause damage to the sail structures.
Unfortunately, the servo-motors are generally unable to change the sail orientation very rapidly. Hence, the servo-motors may be incapable of adequately aligning the sails for minimum resistance in the event that a destructive current force arises. In any event, the servo-motors cannot respond rapidly enough to protect the sail structures from short, strong blasts of current force. Further, the complexity and sensitivity of the servo-motors and the accompanying current detection devices contribute to the possibility of frequent breakdowns and to the necessity for constant supervision and maintenance.
Although these loop-type generator devices are definitely an improvement in the art, they have proven inadequate in several respects. First, the cable or chain to which the individual sail structures are secured occasionally become detached from the suspending wheel or sprocket. When this happens, the sail structures typically collide with surrounding objects and are severely damaged. Even if the device includes a track to guide the individual sail structures, the sail structures sometimes derail and become damaged. Since these sail structures are generally quite large, their replacement is usually both time consuming and costly.
In addition to these structural problems, prior art devices suffer from some notable inefficiencies. For example, the use of a cable or chain to interconnect the separate sail structures necessitates the use of very large suspending wheels or sprockets, together with their associated anchoring structure. This adds significantly to the cost of construction and also materially increases the weight which must be moved before the electric generator begins to function. Thus, the generating efficiency of the device is decreased substantially. Likewise, mounting separate generators and servo-motors on each sail structure adds to the weight of the device and thereby decreases its total generating efficiency.
Accordingly, it would be an improvement in the art to provide a strong, stable electrical generating device which can efficiently produce substantial quantities of electricity from natural air or water currents. Additionally, it would be an improvement in the art to provide a loop-type electrical generating device wherein the several sail structures are quickly and automatically aligned with the air or water current for maximum generating efficiency, yet are rapidly oriented for minimum resistance when destructively forceful currents arise. It would also be an improvement in the art to provide a large capacity wind or water powered electrical generating device which permits the use of a stationary, central electric generator and in which the means for driving the electric generator is light and inexpensive. It would also be an improvement in the art to provide a wind or water powered electric generator having numerous individual sail structures yet in which there is a minimal possibility of said derailment and destruction. Such a device is disclosed and claimed herein.